Indirect Dryers for Biomass Drying—Comparison of Experimental Characteristics for Drum and Rotary Configurations

Abstract

This paper focuses on indirect biomass drying. It compares the operating characteristics of a laboratory-scale drum dryer and a pilot-scale rotary dryer. Before the design of an industrial dryer for a specific material, it is important to experimentally prove the process and to determine the drying characteristics of the material. To verify the portability of experimental results for indirect dryers, a drum dryer with indirect electric heating in a laboratory scale was designed and built to test and study the process of indirect drying. Based on the results obtained on a small-scale device, a prototype of a pilot steam-heated rotary dryer was designed and manufactured. A broad range of experiments with green wood chips and wet bark from open-air storage with moisture contents of 50 to 65 wt % were carried out on both dryers. The drying curves indicating the process, the square and volumetric evaporation capacities, and the drying energy consumption were obtained and compared, and the feasibility of indirect drying for these tested types of biomass was confirmed.

A review of the thermochemistries of biomass gasification and utilisation of gas products

“…Several reviews have been published recently about biomass gasication. [9][10][11][12][13][14][15] These reviews covered various aspects of the technology, including the effects of gasier designs, temperature, pressure, steam-to-biomass (S/B) ratio, steam ow rate, moisture and biomass particle sizes and catalysts on biomass conversion and gas product yields. For example, Hoang et al 10 recently published a review on the key factors that affect the hydrogen yield from steam gasication of lignocellulosic biomass.…”

“…Nitrogen (N 2 ) is also present in the gas product but can come from the gasifying agent and the biomass feedstock. [13][14][15] The yield and quality of the gas product depend on several factors, including mainly the biomass type and particle size, the gasifying agent, the type of gasier (reactor), the ratio of biomass to gasifying agent and other operating conditions of the process. The main equation for the gasication process may be represented as eqn (1):…”

“…Drying can be achieved by using waste heat from the gasication process, and the process of drying is oen accomplished using perforated bin dryers, 13 band conveyors 14 and rotary cascade dryers. 15 Pre-processing of biomass up to pellet production consumes between 100 and 200 kW th per tonne, which can be between 2 and 3% of its energy content. 16 Torrefaction, which involves the mild heating of biomass at temperatures of around 280 °C and atmospheric pressures, has also become an important biomass pre-treatment step to reduce moisture contents and improve the grindability of biomass.…”

Analysis of parameters important for indirect drying of biomass fuel

“…A comparison of the penetration model with the discrete modelling was done in [27]. Recent articles on indirect drying of biomass can be found in [28][29][30].…”

A Novel Rotary Dryer Filled with Alumina Ceramic Beads for the Treatment of Industrial Wastewaters: Numerical Simulation and Experimental Study

“…Besides, the motion trajectory of the ACBs in the airborne phase (Figure 1b) will also affect the installation of the inlet pipe, and thus influence the drying performance of the rotary dryer. Although plentiful studies have been done on the mixing process of the supplied materials, such as wood chips [26], cokes [27], and other agricultural products [28] in rotary dryers, there is little research about the motion of fillers in the rotary drum. As we know, the physical properties, such as density, hardness, and size of fillers are totally different from the supplied materials.…”